Technological Field
The present invention relates to an image forming apparatus and a non-transitory computer-readable recording medium storing an image forming program.
Description of the Related Art
In recent years, various sheets are used in electrophotographic image forming apparatuses (which include copiers, printers, facsimile machines, and multifunctional devices of these machines) that form a toner image on a sheet. To be more specific, in an image forming apparatus, not only typical sheets having a smooth surface (hereinafter referred to as smooth sheet), but also embossed sheets having irregularities on the surface are used as sheets on which to form images. Embossed sheets are used for the cover of printed materials, business cards, posters and the like, for example by utilizing the texture of various irregularities.
When printing is performed on an embossed sheet with an electrophotographic image forming apparatus, however, toner is buried in a recess in the sheet-cross sectional direction in a toner transferring step, and the adhesion between the toner buried in the recess and the fixing member is disadvantageously reduced in the subsequent fixation step.
To be more specific, in the case where printing is performed on the embossed sheet, an air layer is generated between the toner buried in the recess and the fixing member, and the heat transfer from of the fixing member is inhibited by the air layer. Consequently, the fixation performance is degraded, resulting in removal of toner, transfer (smear) of toner to another member, or the like.
Japanese Patent Application Laid-Open No. 2006-78883 (hereinafter, “Patent Literature (PTL)” 1) discloses a technique of reducing the surface roughness of the recording material by use of white and/or transparent toner before forming a color toner image based on input image information for the purpose of preventing density uneveness that is caused in printing on a recording material having a large surface roughness and having no gloss or the like such as an embossed sheet.
In the technique disclosed in PTL 1, however, the color toner is applied after preliminarily reducing the roughness (irregularities) of the recording material by filling the irregularities with transparent and/or white toner, and therefore it is impossible to improve the fixation performance of the color toner while maintaining the texture of the irregularities of the sheet.
To be more specific, with the technique disclosed in PTL 1, it is necessary to apply the color toner after the recess of the recording material is sufficiently reduced by use of transparent and/or white toner to improve the fixation performance of the color toner by reducing the air layer between the recess of the sheet and the fixing member. In this case, the color toner is applied to the surface of the sheet whose irregularities are reduced as much as possible with the transparent and/or white toner, and consequently the texture of the irregularities of the sheet is inevitably impaired, and it is necessary to use a large amount of the transparent and/or white toner.